The invention relates to a coupling for joining fluid pipes, as well as a hydraulic braking circuit for a cycle incorporating such a coupling. A cycle refers to a vehicle with two to three wheels, such as a bicycle or a motorcycle.
It is known from FR 2,129,415 to secure the coupled configuration of a coupling by arranging, on the male element, a stepped outer annular groove with a front portion and a rear portion to cooperate with locking balls of the female element. The female element further comprises a drawer movable relative to a fixed central piston and an outer locking ring that is provided with an inner rim arranged longitudinally between two front and rear inner notches with different depths.
The coupling is coupled by inserting the male element into the female element, and it is not necessary to actuate the locking ring toward the rear, since the drawer pushes the balls back into the front notch of the ring, which keeps the locking ring in the retracted position when the female element is uncoupled from the male element. The movement of the male element in the female element moves the drawer, releases the locking ring, and allows the rear portion of the groove of the male element to align itself with the locking balls. The locking ring is then automatically pushed back by its spring, which aligns the rear notch with the locking balls. The male element can be pushed back toward the front of the female element by the fluid passing in the coupling and by the drawer of the female element to be locked with the locking balls inserted radially between the front portion of the groove and the rear notch of the locking ring. In the coupled configuration, the locking ring cannot be retracted because the locking balls longitudinally interfere with the inner rim of the ring and block the movement of the locking ring toward its retracted position.
To uncouple the coupling, it is necessary to push the male element further into the female element. This in fact places the rear portion of the groove across from the balls, which can thus radially free itself from the inner rim, the locking ring then being able to be retracted toward the rear to accommodate the locking balls in the front notch and release the passage for the male element, which can be removed from the female element.
The dual maneuver necessary for uncoupling prevents the coupling from being uncoupled accidentally, for example under the effect of abrupt accelerations.
U.S. Pat. No. 5,255,699 describes a coupling comprising a male element provided with a valve. The valve comprises a front part that bears against a seat of the male body. The front part extends toward the rear by a rod, around which a sealing gasket and a support for a return spring that pushes the valve back into the closed position against the seat are mounted. The presence of the seat, the minimum diameter of which is smaller than the maximum diameter of the front part, the gasket and the support involves assembling the valve via the rear of the male body.